I had some expired miles. Called MP, spoke with a wonderful supervisor, gave the numbers from the upgrades, and got the miles put into my account in the form of upgrades (I lost a few, but they were expired anyway, so. .. ). It's definitely worth asking! If you do send them in, spend the extra $3 and have them sent certified/registered mail *(whichever one has them sign and you get a receipt). That way there can't be any discrepancy.